Vascular endothelial growth factor expression, S-phase fraction and thymidylate synthase quantitation in node-positive colon cancer: relationships with tumor recurrence and resistance to adjuvant chemotherapy

Brain-derived neurotrophic factor regulates cell motility in human colon cancer

Brain-derived neurotrophic factor (BDNF) is a potent neurotrophic factor that has been shown to affect cancer cell metastasis and migration. In the present study, we investigated the mechanisms of BDNF-induced cell migration in colon cancer cells. The migratory activities of two colon cancer cell lines, HCT116 and SW480, were found to be increased in the presence of human BDNF. Heme oxygenase-1 (HO)-1 is known to be involved in the development and progression of tumors. However, the molecular mechanisms that underlie HO-1 in the regulation of colon cancer cell migration remain unclear. Expression of HO-1 protein and mRNA increased in response to BDNF stimulation. The BDNF-induced increase in cell migration was antagonized by a HO-1 inhibitor and HO-1 siRNA. Furthermore, the expression of vascular endothelial growth factor (VEGF) also increased in response to BDNF stimulation, as did VEGF mRNA expression and transcriptional activity. The increase in BDNF-induced cancer cell migration was antagonized by a VEGF-neutralizing antibody. Moreover, transfection with HO-1 siRNA effectively reduced the increased VEGF expression induced by BDNF. The BDNF-induced cell migration was regulated by the ERK, p38, and Akt signaling pathways. Furthermore, BDNF-increased HO-1 and VEGF promoter transcriptional activity were inhibited by ERK, p38, and AKT pharmacological inhibitors and dominant-negative mutants in colon cancer cells. These results indicate that BDNF increases the migration of colon cancer cells by regulating VEGF/HO-1 activation through the ERK, p38, and PI3K/Akt signaling pathways. The results of this study may provide a relevant contribution to our understanding of the molecular mechanisms by which BDNF promotes colon cancer cell motility.

Thymidylate synthase gene polymorphism and survival of colorectal cancer patients receiving adjuvant 5-fluorouracil

Limited studies indicate a possible association of 5'-UTR thymidylate synthase enhancer region polymorphism and treatment outcome in patients medicated with 5-fluorouracil (5-FU). The study was designed to verify the relationship in patients with colorectal cancer (CRC), a Polish population that received 5-FU-based adjuvant chemotherapy. The study analyzed 145 Astler-Coller B2 and C CRC patients. Genotyping for a variable number of tandem repeats and G to C single-nucleotide polymorphism in the 5'-UTR of the thymidylate synthase (TS) gene was carried out. TS genotypes were classified into high expression (high TS) and low expression types (low TS). High TS was found in 22.8% of patients. The right-side tumors were more frequently associated with high TS than the left-side tumors (p=0.024). High TS was only found in 9.3% of rectal tumors, but in 29.7% of colon cancers (p=0.0042). Disease-free survival after 20 months (DFS 20) was longer in subjects with low TS than in high TS (p=0.043). Patients who underwent chemotherapy had longer DFS 20 in the low TS than in the high TS subgroup (p=0.051). The low TS was found to be an independent good prognostic factor for DFS 20 in the whole group as well as in the subgroup treated with chemotherapy (p=0.024 and p=0.034, respectively). Patients with low TS did not show any differences in DFS 20 whether they were treated with adjuvant chemotherapy or not. Proximal CRC tumors are characterized by higher TS expression genotypes than distal tumors, and are at significantly greater risk of early recurrence during the first 20 months after surgery.

Predictive value of vascular endothelial growth factor overexpression in early relapse of colorectal cancer patients after curative resection

BACKGROUND

Preclinical and clinical studies have indicated that vascular endothelial growth factor (VEGF) is the predominant angiogenic factor. Recently, there was a consistent trend of poorer survival rates in colorectal cancer (CRC) patients of earlier relapse. The purpose of this study was to investigate novel predictors of early relapse in stage I-III CRC and further to determine their correlation with disease outcomes.

MATERIALS AND METHODS

We retrospectively analyzed clinicopathological features and VEGF expression by immunohistochemical staining in 100 stage I-III CRC patients undergoing curative resection to identify predictors of postoperative early relapse.

RESULTS

Among 100 patients, 40 patients were classified into early relapse group, and 60 patients were categorized into non-early relapse group. A multivariate logistic regression analysis showed that vascular invasion (P = 0.048), perineural invasion (P = 0.042), VEGF overexpression (P = 0.023), and high postoperative carcinoembryonic antigen (CEA) levels (P = 0.004) were independent predictors of early relapse. Additionally, we found that with more predictors such as the combined incidence of vascular invasion, perineural invasion, VEGF overexpression, and postoperative CEA levels are involved, the incidence of early postoperative relapse increases. Moreover, VEGF overexpression predicted not only early postoperative relapse but also disease-free survival (P < 0.001) and overall survival (P = 0.002).

CONCLUSIONS

This study suggests that VEGF overexpression is an important predictor of early postoperative relapse in patients with stage I-III CRC and may help identify patients who would benefit from intensive follow-up and therapeutic programs.

Thymidylate synthase expression and prognosis in colorectal cancer: a meta-analysis of colorectal cancer survival data

BACKGROUND

Although many studies have investigated the prognostic effect of thymidylate synthase (TS) in colorectal cancer, no consensus has been reached. The aim of this meta-analysis was to obtain a more precise estimate of the prognostic significance of TS expression in localized cancers treated by curative resection and adjuvant chemotherapy.

MATERIALS AND METHOD

Seventeen eligible studies reporting survival in 2,893 patients stratified by TS expression were pooled using a fixed- or random-effects model. The main outcome measure was hazard ratio (HR).

RESULTS

The overall HR for overall survival was 1.01 (95% CI 0.74-1.39, p=0.947), with an I2 of 64.4%. The total HR for disease-free survival was 1.36 (95% CI 0.97-1.89, p=0.072), with an I2 of 75.8%. In the TS protein-tested subgroup, the total HR for disease-free survival was 1.72 (95% CI 1.02-2.89, p=0.042), with an I2 of 81.3%.

CONCLUSION

Our meta-analysis showed that, in the adjuvant setting, TS expression does not predict a poorer disease-free survival or a worse overall survival. Therefore, we believe that it is inappropriate to regard TS expression as a prognostic factor for patients with stage II and stage III colorectal cancer treated by surgery and adjuvant chemotherapy.

Co-existence of cyclin D1 and vascular endothelial growth factor protein expression is a poor prognostic factor for UICC stage I-III colorectal cancer patients after curative resection

BACKGROUND

Angiogenesis plays an important role in the progression of colorectal cancer (CRC). Studies have indicated vascular endothelial growth factor (VEGF) is the predominant angiogenic factor. Cyclin D1 (CCND1) induces production of VEGF and is required for migration of blood vessels. Our aim was to determine the roles of CCND1 and VEGF overexpression in CRC patients.

METHODS

We analyzed clinicopathological features, VEGF and CCND1 expressions by immunohistochemical (IHC) staining in 100 stage I-III CRC patients (44 were postoperative relapsed; 56 were postoperative non-relapsed) to determine the correlation between clinicopathologic features and co-existence of CCND1 and VEGF. Furthermore, the clinical outcomes of co-existence of CCND1 and VEGF were investigated.

RESULTS

Multivariate analysis showed vascular invasion (P = 0.019), VEGF overexpression (P = 0.033), and high postoperative serum carcinoembryonic antigen (CEA) levels (P = 0.022) were independent predictors of postoperative relapse. Co-existence of CCND1 and VEGF overexpression had significantly poorer disease-free survival rates (P  = 0.004) and overall survival rates (P = 0.001) than other phenotypes.

CONCLUSIONS

Co-existence of CCND1 and VEGF overexpression would potentially assist in TNM staging systems to predict the prognosis of these patients who would benefit from intensive follow-up and therapeutic programs.

Management of colorectal cancer patients after resection of liver metastases: can we offer a tailored treatment?

Surgical resection remains the only option of cure for patients with colorectal liver metastases, and no patient should be precluded from surgery. There is much controversy not only regarding the most appropriate therapeutic approach in the neoadjuvant setting but also after surgery is performed. Many patients will experience early relapses but others will be long survivors. We need to establish reliable prognostic and predictive factors to offer a tailored treatment. Several prognostic factors after metastasectomy have been identified: high C-reactive protein levels, a high neutrophil-lymphocyte ratio, elevated neutrophil count and low serum albumin are related to a worst outcome. Elevated CEA and Ki 67 levels, intrahepatic and perihepatic lymph node invasion are also some of the markers related to a worst outcome. In contrast, the administration of preoperative chemotherapy has been associated with a better prognosis after hepatectomy. The administration of adjuvant chemotherapy should be done taking in consideration these factors. Regarding predictive factors, determination of ERCC1, TS, TP and DPD and UGT1 polymorphisms assessment could be considered prior to chemotherapy administration. This would avoid treatment related toxicities and increase this population quality of life.

miR-192/miR-215 influence 5-fluorouracil resistance through cell cycle-mediated mechanisms complementary to its post-transcriptional thymidilate synthase regulation

Thymidylate synthase (TYMS) is a target of the most widely used chemotherapeutic agents against gastrointestinal malignancies, the fluoropyrimidine-based therapy. TYMS expression levels have been identified as predictive biomarkers for 5-fluoruracil (FU) response in colorectal cancer, but their clinical utility remains controversial. The complexity of fluoropyrimidine response must require more mechanisms that currently have not been completely elucidated. In this context, microRNAs (miRNA) may play a role in modulating chemosensitivity. By carrying out an in silico analysis coupled to experimental validation, we detected that miR-192 and miR-215 target TYMS expression in colorectal cancer cell lines. However, downregulation of TYMS by these miRNAs does not sensitize colorectal cancer cell lines to FU treatment. The overexpression of miR-192/215 significantly reduces cell proliferation by targeting cell cycle progression. This effect was partially associated with p53 status, because reduction of cell proliferation and cell cycle arrest was associated with p21 and p27 induction. The decrease of S-phase cells by these miRNAs mitigates the effects of S phase-specific drugs and suggests that other mechanisms different from TYMS overexpression are essential to direct FU resistance. Finally, ectopic expression of miR-192/215 might have stronger impact to predict FU response than TYMS inhibition. Prospective studies to elucidate the role of these miRNAs as predictive biomarkers to FU are necessary.

Relationship of polymorphism of the tandem repeat sequence in the thymidylate synthase gene and the survival of stage III colorectal cancer patients receiving adjuvant 5-flurouracil-based chemotherapy

BACKGROUND

The aim of this study was to determine whether the different polymorphisms in the thymidylate synthase (TS) gene, novel G>C single nucleotide polymorphism (SNP) and variable number of tandem repeat (VNTR), may be related with disease-free survival (DFS) in patients with stage III colorectal cancer receiving adjuvant chemotherapy.

METHODS

The study included 201 patients with pathologic TNM stage III colon cancer who received adjuvant 5-fluorouracil (5-FU)-based chemotherapy after surgery. DNA was extracted from fresh tumor tissue and sequenced. Patients with TS genotypes of 2R3G, 3C3G, or 3G3G were assigned to a high expression group, and those with 2R2R, 2R3C, or 3C3C, to a low expression group.

RESULTS

Frequencies of the TS tandem repeat polymorphisms among the tumor genotypes were 6.0% in 2R2R, 25.4% in 2R3R, and 68.7% in 3R3R. The low expression group included 52 patients (25.9%), and the high expression group included 149 patients (74.1%). Groups classified according to possession of VNTR, SNP, and low- or high-expression genotypes did not differ significantly in DFS. In multivariate analysis, only tumor stage showed significant prognostic value (hazard ratio (HR) 2.05, 95% CI = 1.24-3.37, P = 0.005).

CONCLUSIONS

TS polymorphisms do not predict clinical outcome of colorectal cancer patients treated with adjuvant 5-FU-based chemotherapy.

Local recurrence in mismatch repair-proficient colon cancer predicted by an infiltrative tumor border and lack of CD8+ tumor-infiltrating lymphocytes

PURPOSE

The identification of colon cancer patients at high risk of local recurrence is necessary to improve the selection of patients for more tailored treatment protocols. The aim of this study was to develop a predictive model of local recurrence by assessing the independent predictive effect of 7 clinicopathologic features, 24 protein markers of tumor progression, and their multifeature combinations in mismatch repair-proficient colon cancers.

EXPERIMENTAL DESIGN

Immunohistochemistry for 24 protein markers was done on 269 patients with complete clinicopathologic data. After univariate and multivariable analyses, independent predictors of local recurrence were identified and their multifeature combinations were analyzed. Kaplan-Meier and Cox proportional hazards regression were done for survival analysis.

RESULTS

Local recurrence was observed in 119 patients (55.8%). Independent predictors of tumor recurrence were lymph node involvement (P = 0.006), absence of CD8+ tumor-infiltrating lymphocytes (TIL; P < 0.001), and infiltrative tumor margin (P < 0.001). This independent effect persisted after adjusting for adjuvant therapy. Risk of recurrence was 0.75 and the 5-year survival rate was 8.8% in patients with these three adverse features. Node-negative patients with an infiltrative tumor margin and absence of CD8+ TILs were identified as high risk with a probability of 0.55 for recurrence and a 60% 5-year survival rate. The remaining node-negative cases fared significantly better with risks ranging from 8% to 26% and 5-year survival rates reaching 97.6%.

CONCLUSIONS

An infiltrative tumor margin and absence of CD8+ TILs are highly predictive of local recurrence in node-negative mismatch repair-proficient colon cancer and may help to identify high-risk patients who may benefit from adjuvant chemotherapy.

Specific imaging of VEGF-A expression with radiolabeled anti-VEGF monoclonal antibody

Vascular endothelial growth factor-A (VEGF-A) is one of the most important angiogenic factors. Here, we studied in a nude mouse model whether the expression of VEGF-A in a tumor could be imaged with a radiolabeled anti-VEGF antibody. The humanized anti-VEGF-A antibody A.4.6.1. (bevacizumab), which is reactive with all VEGF-A isoforms, was radiolabeled with In-111 or with I-125. The accumulation of the radiolabeled antibodies in VEGF-A expressing tumors (LS174T) in nude mice was examined in biodistribution studies and by gamma camera imaging. The uptake of the In-111-bevacizumab in the tumor at 3 days p.i. was significantly higher than that of I-125-bevacizumab (19.4 +/- 7.0 %ID/g vs. 9.6 +/- 3.3 %ID/g, p = 0.04). Coinjection of an excess unlabeled antibody resulted in a significant decrease in radioactivity concentration in the tumor (<2.9 +/- 1.9 %ID/g, p < 0.005), indicating VEGF-mediated antibody uptake. Highest uptake in the tumor was observed at relatively low antibody protein doses (<3 microg) (20-25 %ID/g). VEGF-A-expressing tumors could be clearly visualized on planar scintigraphic images from 24-hr post injection onwards. In conclusion, VEGF-A expression in tumors can be visualized specifically with radiolabeled anti-VEGF-A-mAb.

The potential of anti-vascular endothelial growth factor therapy in metastatic breast cancer: clinical experience with anti-angiogenic agents, focusing on bevacizumab

The importance of angiogenesis in tumour growth and development is well known. Overexpression of vascular endothelial growth factor (VEGF), the key mediator of angiogenesis, is associated with poor prognosis in breast cancer. As a result, several therapeutic agents that inhibit the actions of VEGF or its receptors are currently in development for use in metastatic breast cancer (MBC). This review describes the function of VEGF in normal and tumour angiogenesis, explores the rationale behind the use of anti-VEGF therapy in MBC and details the therapeutic impact of such agents on tumour vasculature. Clinical data from trials of anti-VEGF agents in MBC are discussed, with a particular focus on the efficacy and safety of bevacizumab, the anti-VEGF agent at the most advanced stage of development in this tumour type. Future potential uses of bevacizumab in breast cancer are introduced.

Molecular profiling and risk stratification of adenocarcinoma of the colon

Staging systems are used to predict the clinical and biologic behavior of tumors. This manuscript examines several molecular markers that hope to improve staging for colon cancer. It is unclear if a molecular marker, genetic signature, or a combination of histologic, genetic, and molecular parameters will provide the best prognostic information. What is clear is that more accurate staging tools are needed so patients receive the best therapy.

Prognostic value of carcinoembryonic antigen and vascular endothelial growth factor tumor tissue content in colorectal cancer

AIM

This study was designed to assess the prognostic significance of the combined measurement of vascular endothelial growth factor (VEGF) and carcinoembryonic antigen (CEA) tissue content with respect to relapse-free and overall survival of patients with colorectal cancer (CRC).

METHODS

Quantitative evaluation of VEGF and CEA content was performed on protein extracts obtained from tissue biopsies from 69 CRC patients and 15 healthy donors.

RESULTS

VEGF significantly correlated with CEA content of either tumor tissues (rho = 0.55, p < 0.0001) or corresponding normal mucosa (rho = 0.34, p < 0.005). General regression analyses demonstrated that CEA was an independent predictor of VEGF tissue content either in CRC biopsies (regression coefficient = 0.57, p < 0.0001) or normal mucosa (regression coefficient = 0.25, p < 0.05). Cox proportional hazards survival analysis showed that tumor tissue content of both VEGF and CEA had an independent prognostic value in predicting both relapse-free (hazards ratio = 5.98, p = 0.002) and overall (hazards ratio = 4.73, p = 0.007) survival, irrespective of Dukes' stage. Kaplan-Meier analysis demonstrated that an elevated tumor content of both CEA and VEGF had a negative prognostic value in respect to either relapse-free (log-rank test: 10.4, p = 0.001) or overall survival (log-rank test: 7.33, p = 0.007).

CONCLUSION

Tumor tissue VEGF and CEA content determination might add useful prognostic information in the management of patients with CRC.

Phase II study of interleukin-2 and 13-cis-retinoic acid as maintenance therapy in metastatic colorectal cancer

PURPOSE

We have previously shown that low-dose interleukin-2 (IL-2) and 13-cis-retinoic acid (13-cis-RA) improved lymphocyte and natural killer (NK) cell count of patients with advanced tumors showing a clinical benefit from chemotherapy. The primary endpoint of this study was to ask whether IL-2 and 13-cis-RA improved (> or =30%) lymphocyte and NK cell count in patients with metastatic colorectal cancer (MCRC) that had a clinical benefit from induction chemotherapy. Secondary endpoint was the evaluation of toxicity, progression-free survival (PFS), and overall survival (OS).

PATIENTS AND METHODS

Forty patients with MCRC, showing a clinical benefit from chemotherapy, were treated with subcutaneous low-dose IL-2 (1.8 x 10(6) IU) and oral 13-cis-RA (0.5 mg/kg) in order to maintain responses and improve survival through the increase of lymphocyte and NK cells. The biological parameters and the clinical outcome of these patients were compared with those of a control group of patients (80) with a similar disease status, including clinical benefit from chemotherapy.

RESULTS

The most common adverse events were mild cutaneous skin rash and fever. After 4 months and 2 years of biotherapy, a statistically significant improvement was observed in lymphocyte and number of NK cells with respect to baseline values and to controls. After a median follow-up of 36 months, median PFS was 27.8 months, while median OS was 52.9 months.

CONCLUSION

These data show that maintenance immunotherapy with low-dose IL-2 and oral 13-cis-RA in patients with MCRC showing a clinical benefit from chemotherapy is feasible, has a low toxicity profile, improves lymphocyte and NK cell count. An improvement in the expected PFS and OS was also observed. A randomized trial is warranted.

Predictive role of thymidylate synthase, dihydropyrimidine dehydrogenase and thymidine phosphorylase expression in colorectal cancer patients receiving adjuvant 5-fluorouracil

OBJECTIVE

The combined assessment of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) gene expressions in metastatic colorectal cancer has been reported to be able to predict the efficacy of fluoropyrimidine-based chemotherapy. In order to evaluate the prognostic role in the adjuvant setting, we investigated the TS, DPD and TP expression in primary tumors of colorectal cancer patients treated with 5-fluorouracil (5-FU).

METHODS

TS, DPD and TP expression levels were determined by immunohistochemistry in paraffin-embedded primary tumor tissues from 62 patients with Dukes' stage B and C colorectal cancers who underwent surgery and received adjuvant systemic chemotherapy with 5-FU. The median follow-up was 90 months (range 17-127).

RESULTS

Dukes' stage C cancer and high TS expression were independent markers of poor prognosis for disease-free survival (DFS; p = 0.0009 and p = 0.007, respectively) and overall survival (OS; p = 0.0005 and p = 0.011, respectively). By multivariate analysis, patients with high DPD expression had significantly shorter DFS (p = 0.007) and OS (p = 0.005) compared to patients with low DPD expression. In the combined analysis of 2 markers, patients with low TS and low DPD had the best outcome in terms of DFS (p = 0.007) and OS (p = 0.03). The analysis of all 3 proteins showed that the patients with low expression of all 3 markers had significantly longer DFS (p = 0.04) and OS (p = 0.01) than patients with a high value of any one of the protein expressions. However, the joint analysis of 3 markers (group with TS-/DPD-/TP-) could not identify a subgroup of patients with a better prognosis compared to the analysis of 2 markers (group with TS-/DPD-). The analysis of Dukes' stage C cancer patients confirmed a significant benefit in terms of DFS and OS (p = 0.001 and p = 0.006, respectively) when all 3 markers had low expression. We also found a positive significant correlation between TS and TP protein expression (p = 0.033).

CONCLUSIONS

This retrospective investigation suggests that the combined assessment of TS and DPD may be useful to evaluate the prognosis of patients with Dukes' B and C colon carcinoma receiving 5-FU adjuvant chemotherapy. The role of TP as a predictor for 5-FU-based therapy needs further investigations.

ASCO 2006 Update of Recommendations for the Use of Tumor Markers in Gastrointestinal Cancer

Purpose

To update the recommendations for the use of tumor marker tests in the prevention, screening, treatment, and surveillance of gastrointestinal cancers.

Methods

For the 2006 update, an update committee composed of members from the full Panel was formed to complete the review and analysis of data published since 1999. Computerized literature searches of Medline and the Cochrane Collaboration Library were performed. The Update Committee's literature review focused attention on available systematic reviews and meta-analyses of published tumor marker studies.

Recommendations and Conclusion

For colorectal cancer, it is recommended that carcinoembryonic antigen (CEA) be ordered preoperatively, if it would assist in staging and surgical planning. Postoperative CEA levels should be performed every 3 months for stage II and III disease for at least 3 years if the patient is a potential candidate for surgery or chemotherapy of metastatic disease. CEA is the marker of choice for monitoring the response of metastatic disease to systemic therapy. Data are insufficient to recommend the routine use of p53, ras, thymidine synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase, microsatellite instability, 18q loss of heterozygosity, or deleted in colon cancer (DCC) protein in the management of patients with colorectal cancer. For pancreatic cancer, CA 19-9 can be measured every 1 to 3 months for patients with locally advanced or metastatic disease receiving active therapy. Elevations in serial CA 19-9 determinations suggest progressive disease but confirmation with other studies should be sought. New markers and new evidence to support the use of the currently reviewed markers will be evaluated in future updates of these guidelines.

Association of VEGF genetic polymorphisms with prostate carcinoma risk and clinical outcome

OBJECTIVES

Vascular endothelial growth factor (VEGF) is a potent stimulus of angiogenesis that has an important role in many human malignancies including prostate carcinoma (PCa). We evaluated the role of the functional VEGF polymorphisms as genetic markers for PCa susceptibility and prognosis.

METHODS

The study included 101 patients with PCa and [corrected] 100 age-matched healthy men. The VEGF genotypes -1154G>A were identified by allele-specific polymerase chain reaction (AS-PCR) and the genotypes -634G>C and 936C>T were identified by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR).

RESULTS

A negative association was found between VEGF -1154AA genotype and PCa risk (OR=0.27; P=0.009). Furthermore, the presence of the VEGF -1154A allele appeared to be associated with a decreased [corrected] risk of higher tumor grade (OR=0.37; P=0.01). A significant increased risk of prostate cancer was associated with the VEGF -634 (GC+CC) combined genotype (OR=1.95; P=0.02). The VEGF -634C allele was associated with the aggressive phenotype of prostate cancer as defined by the high histological grade (OR=3.48; P=0.007). The VEGF -1154A/-634G haplotype was negatively associated with PCa risk (OR=0.48; P=0.005) and high tumor grade compared to low grade (OR=0.37; P=0.02).

CONCLUSIONS

Genetic variations in the VEGF may predict not only PCa risk but also tumor aggressiveness.

Microvessel density and VEGF expression are prognostic factors in colorectal cancer. Meta-analysis of the literature

We performed a meta-analysis of all published studies relating intratumoural microvessel density (MVD) (45 studies) or vascular endothelial growth factor (VEGF) expression (27 studies), both reflecting angiogenesis, to relapse free (RFS) and overall survival (OS) in colorectal cancer (CRC). For each study, MVD impact was measured by risk ratio between the two survival distributions with median MVD as cutoff. Eleven studies did not mention survival data or fit inclusion criteria, six were multiple publications of same series, leaving 32 independent studies for MVD (3496 patients) and 18 for VEGF (2050 patients). Microvessel density was assessed by immunohistochemistry, using antibodies against factor VIII (16 studies), CD31 (10 studies) or CD34 (seven studies). Vascular endothelial growth factor expression was mostly assessed by immunohistochemistry. Statistics were performed for MVD in 22 studies (the others lacking survival statistics) including nine studies (n = 957) for RFS and 18 for OS (n = 2383) and for VEGF in 17 studies, including nine studies for RFS (n = 1064) and 10 for OS (n = 1301). High MVD significantly predicted poor RFS (RR = 2.32 95% CI: 1.39-3.90; P < 0.001) and OS (RR = 1.44; 95% CI: 1.08-1.92; P = 0.01). Using CD31 or CD34, MVD was inversely related to survival, whereas it was not using factor VIII. Vascular endothelial growth factor expression significantly predicted poor RFS (RR = 2.84; 95% CI: 1.95-4.16) and OS (RR=1.65; 95% CI: 1.27-2.14). To strengthen our findings, future prospective studies should explore the relation between MVD or VEGF expression and survival or response to therapy (e.g. antiangiogenic therapy). Assessment of these angiogenic markers should be better standardised in future studies.

Influence of thymidylate synthase gene polymorphisms on the survival of colorectal cancer patients receiving adjuvant 5-fluorouracil

The present study aimed to prospectively investigate the influence of thymidylate synthase (TS) polymorphisms (5'-TSER, 3'-TSUTR) on the disease-free survival (DFS) and overall survival (OS) of patients with colorectal cancer (CRC) who were treated with adjuvant 5-fluorouracil (5-FU) therapy. Patients were followed up for 19+/-14 months (median+/-SD). TS genotypes were determined from the peripheral blood mononuclear cells of 166 patients by polymerase chain reaction-polyacrylamide gel electrophoresis and restriction fragment length polymorphism methods. 5'-TSER 3R homozygotes showed significantly longer DFS (P = 0.048) and OS (P = 0.009). The 5'-TSER and 3'-TSUTR genotype combination groups showed a significant difference for DFS (P = 0.039) and OS (P = 0.029). Significantly better DFS (P = 0.049) and OS (P = 0.043) were observed for 6 bp/6 bp genotypes in 5'-TSER heterozygotes (n = 80). Based on this, and on hazard ratios obtained by Cox regression analysis of the DFS of genotype-combinations, the patients were classified as belonging to prognostic groups A and B. The DFS and OS of these two groups showed a highly significant difference (P = 0.002 and 0.001). In the multivariate Cox regression model, beside tumour location, the prognostic classification (groups A and B) proved to be an independent prognostic factor. Our data suggest that those TS genotypes and their combinations (group A: 3R/3R with any 3'-TSUTR genotype and 2R/3R with 6 bp/6 bp), which have been reported earlier as having high TS expression, predict significantly longer DFS and OS. We found that a combination of germline TS polymorphisms is an independent prognostic marker in selecting CRC patients with worse prognosis, and it may be worthwhile to examine whether these patients would benefit from an alternative therapy.

Adjuvant therapy of colon cancer: current status and future developments

Options for the adjuvant therapy of resected stage III colon cancer have expanded beyond the previously well-accepted standard of 5-fluorouracil (5-FU) combined with leucovorin. The Xeloda in Adjuvant Colon Cancer Therapy (X-ACT) study confirmed that capecitabine (Xeloda) is at least as effective and is less toxic than a bolus 5-FU and leucovorin regimen for patients with stage III colon cancer. This study, in addition to National Surgical Adjuvant Breast and Bowel Project (NSABP) C-06, which demonstrated the equivalence of tegafur-uracil (UFT)/leucovorin with 5-FU/leucovorin, provides support for use of oral fluoropyrimidines for adjuvant therapy. Support for use of multiagent chemotherapy has been provided by the European MOSAIC study, which demonstrated a significant improvement in 3-year disease-free survival for the addition of oxaliplatin (Eloxatin) to infusional 5-FU and leucovorin (FOLFOX). Although adding irinotecan (Camptosar) to a bolus 5-FU and leucovorin regimen did not improve outcome in the adjuvant setting, the PETACC studies are evaluating the combination of infusional 5-FU, leucovorin, and irinotecan. In contrast to agreement on the appropriateness of therapy for stage III colon cancer, adjuvant therapy for patients with stage II disease remains controversial. Future advances in adjuvant therapy may include targeted therapies. Based on data demonstrating efficacy for the monoclonal antibodies bevacizumab (Avastin) and cetuximab (Erbitux) in the metastatic setting, clinical trials adding these agents to standard chemotherapy have been initiated in the adjuvant setting. Specifically, one U.S. cooperative group trial will evaluate the addition of bevacizumab to chemotherapy, a second will assess the addition of cetuximab, and a third trial will evaluate FOLFOX, infusional 5-FU/leucovorin (FOLFIRI), and FOLFOX followed by FOLFIRI. Finally, a study for patients with stage II disease and adverse prognostic factors will open. An important consideration in the new clinical trials is an assessment of molecular markers that either predict response or resistance to therapy or provide other prognostic information.

Predictive factors for response to chemotherapy in colorectal cancer patients

Colorectal cancer represents a major health problem in the western world. A lot of drugs have been employed in treatment of this disease, but only few data are available about predictive factors for response to anticancer treatments in colorectal cancer. Aim of this paper is to review the main data about this investigation field. Using a Medline database search (1966-2003) we reviewed all the relevant papers that investigate clinical and molecular predictors for response to the main drugs used in the treatment of colorectal cancer patients, both in adjuvant and in advanced setting. Moreover we comprehensively reviewed all the data published in abstract form during the most significant international meetings. Our review put in evidence the most important predictive factors for response in colorectal cancer patients treated with anticancer chemotherapy both in adjuvant and in advanced setting. The predictive factors are clustered on the basis of the different anticancer drugs. The results of this review provide the rationale basis for personalizing anticancer treatment in colorectal cancer patients by molecular and clinical features, aiming to improve response rate and reduce toxicities.

Clinical Trial Designs for Predictive Marker Validation in Cancer Treatment Trials

Current staging and risk-stratification methods in oncology, while helpful, fail to adequately predict malignancy aggressiveness and/or response to specific treatment. Increased knowledge of cancer biology is generating promising marker candidates for more accurate diagnosis, prognosis assessment, and therapeutic targeting. To apply these exciting results to maximize patient benefit, a disciplined application of well-designed clinical trials for assessing the utility of markers should be used. In this article, we first review the major issues to consider when designing a clinical trial assessing the usefulness of a predictive marker. We then present two classes of clinical trial designs: the Marker by Treatment Interaction Design and the Marker-Based Strategy Design. In the first design, we assume that the marker splits the population into groups in which the efficacy of a particular treatment will differ. This design can be viewed as a classical randomized clinical trial with upfront stratification for the marker. In the second design, after the marker status is known, each patient is randomly assigned either to have therapy determined by their marker status or to receive therapy independent of marker status. The predictive value of the marker is assessed by comparing the outcome of all patients in the marker-based arm to that of all of the patients in the non–marker-based arm. We present detailed sample size calculations for a specific clinical scenario. We discuss the advantages and disadvantages of the two trial designs and their appropriateness to specific clinical situations to assist investigators seeking to design rigorous, marker-based clinical trials.

Angiogenesis in colorectal cancer: therapeutic implications and future directions

This article discusses the therapeutic implications and future directions of angiogenesis in colorectal cancer.

Thymidylate synthase expression and prognosis of patients with gastrointestinal cancers receiving adjuvant chemotherapy: a review

BACKGROUND AND AIMS

Many studies have been published that report an association between thymidylate synthase (TS) and response to fluoropyrimidine-based chemotherapy and the overall outcome of patients with gastrointestinal cancer. The results have given rise to the possibility that, by determination of TS levels, the physician may decide if the patient has a potential benefit from fluoropyrimidine-based treatment, similar to measurements of oestrogen receptors in breast cancer. The purpose of this review is to summarize critically the reports on TS measurement in gastrointestinal cancer, focusing on the adjuvant fluoropyrimidine treatment situation.

METHODS

We reviewed more than 20 studies that reported the association of TS with the clinical outcome in patients with gastrointestinal cancer who had undergone complete resection of the primary tumour only or were receiving additional adjuvant chemotherapy.

RESULTS

Patients with metastasized disease who expressed high TS levels display a low probability of responding to fluoropyrimidine-based treatment and have a poorer survival rate. Patients with high TS levels who undergo complete surgical resection of the primary tumour also have a poorer prognosis than those with tumours with low TS expression. In contrast to advanced disease and to surgery alone, patients with high TS levels appear to benefit, especially, from adjuvant fluoropyrimidine-based chemotherapy after complete primary tumour resection, while patients with low TS levels do not.

CONCLUSION

Patients with gastrointestinal cancers that express high TS levels have a poor prognosis with regard to fluoropyrimidine-based palliative chemotherapy or complete primary tumour resection. In contrast, patients with high TS levels might benefit from adjuvant fluoropyrimidine-based treatment after primary tumour resection. However, additional prospective studies are mandatory to define the precise role of TS in adjuvant therapy.

Expression of vascular endothelial growth factor, hypoxia inducible factor 1alpha, and carbonic anhydrase IX in human tumours

AIMS

To measure vascular endothelial growth factor (VEGF-A) mRNA in a large, diverse cohort of tumours and to investigate whether VEGF-A expression is associated with markers of hypoxia, including hypoxia inducible factor 1alpha (HIF-1alpha) and carbonic anhydrase IX (CA9).

METHODS

The expression of VEGF-A and CA9 was assessed in 5067 fresh frozen human tissue samples and 238 cell lines by DNA microarray analysis. In addition, tissue microarrays were constructed from 388 malignancies to investigate the expression of VEGF-A and HIF-1alpha by in situ hybridisation and immunohistochemistry, respectively.

RESULTS

VEGF-A was significantly upregulated in primary malignancies of the breast, cervix, colon and rectum, oesophagus, head and neck, kidney, ovary, skin, urinary system, and white blood cells by DNA microarray analysis. However, VEGF-A expression only correlated with CA9 expression in renal tissues. In the tissue microarrays, HIF-1alpha positive cores showed a significant increase in VEGF-A expression in lung, ovary, soft tissue, and thyroid malignancies.

CONCLUSIONS

The expression of VEGF-A is upregulated in a large proportion of human malignancies, and may be associated with markers of hypoxia. VEGF-A expression can be induced in the absence of hypoxia and hypoxia does not always provoke VEGF-A upregulation in tumours.

Molecular lesions in colorectal cancer: impact on prognosis? Original data and review of the literature

BACKGROUND

In the Dukes' B and C stages of colorectal carcinoma there are considerable variations in the observed courses of the disease. Since post-operative chemotherapy in patients with Dukes' C (node-positive) colon carcinoma has been demonstrated to be effective in improving overall-survival, a more exact prognosis assessment gains additional significance and therapeutic relevance.

DISCUSSION

One also hopes to derive improved prognostic factors from the clarification of the molecular pathogenesis. Because of its frequency and the accessibility and recognizability of its developmental stages colorectal carcinoma is among the best investigated of all solid tumors. Despite a multitude of suggested molecular candidate markers none of these changes has yet been able enter the everyday life of the clinic. However, it is to be expected that some of the molecular alterations presently discussed will gain importance before long in the clinical treatment of patients with colorectal carcinoma.

CONCLUSION

Considering also our own findings, this review presents the latest developments in the scientific discussion of the tumor suppressor/oncogenes p53, k-ras, and DCC, biochemical determinants of the 5-fluorouracil metabolism, and defects of the DNA repair system.

Colorectal cancer in the adjuvant setting: perspectives on treatment and the role of prognostic factors

In patients with stage III colorectal cancer (CRC) who have undergone potentially curative resection, adjuvant treatment with 6 months' of 5-fluorouracil (5-FU) plus folinic acid (FA) is generally accepted as standard treatment and leads to a 5% to 10% improvement in absolute survival when compared with a no-chemotherapy control. In stage II CRC, the benefit of adjuvant chemotherapy has yet to be established. In metastatic CRC, randomized trials of irinotecan have consistently demonstrated that use of the drug, either alone or in combination with 5-FU/FA, prolongs survival. To investigate whether this benefit can be extended to patients with earlier disease, a series of multicenter trials are randomizing stage III colon cancer patients to adjuvant 5-FU/FA regimens with or without the addition of irinotecan. The role of adjuvant irinotecan is also being assessed in stage II colon cancer and in patients with rectal tumors. The risk/benefit ratio of adjuvant therapy in both stage III and stage II disease would be decreased if patients at the highest risk of relapse could be identified. Data from retrospective analyses suggest that DNA indexes, angiogenesis and some genetic/biological markers (loss of heterozygosity at chromosome 18 and the presence of microsatellite instability) identify prognostic differences in colon cancer patients. Their value as a guide to the intensity of adjuvant therapy required should be tested by randomized trial, as should the use of markers such as thymidilate synthase overexpression as a means of tailoring drug choice to tumor characteristics.

Clinical significance of angiogenesis in gastrointestinal cancers: a target for novel prognostic and therapeutic approaches

OBJECTIVE

To review the current data on the prognostic and therapeutic implications of tumor angiogenesis in gastrointestinal cancers.

SUMMARY BACKGROUND DATA

Numerous studies have evaluated the prognostic value of tumor angiogenesis and the potential role of antiangiogenic therapy in various gastrointestinal cancers.

METHODS

A Medline literature search was conducted using "angiogenesis" or the names of various angiogenic factors in combination with the names of gastrointestinal cancers as the key words.

RESULTS

Several studies have demonstrated a significant prognostic impact of tumor microvessel density and tumor expression of angiogenic factors, in particular vascular endothelial growth factor (VEGF), in various gastrointestinal cancers. A few studies have suggested that circulating VEGF might be a useful prognostic marker. However, results were not consistent across all studies and were limited by the retrospective nature of most studies. Antiangiogenic therapy has been shown to be effective against all common gastrointestinal cancers in preclinical studies, but currently there are few clinical data with regard to antiangiogenic therapy in gastrointestinal cancers.

CONCLUSIONS

There is mounting evidence to suggest that assessment of tumor angiogenesis might provide a novel approach of prognostication in patients with gastrointestinal cancers. However, current results from retrospective studies need to be validated by prospective studies. Antiangiogenic therapy is a promising strategy of cancer treatment that might be particularly useful in combination therapy for unresectable cancers or as an adjuvant therapy for resectable tumors.

Evaluation of the Prognostic Role of Vascular Endothelial Growth Factor and Microvessel Density in Stages I and II Breast Cancer Patients

In this study, we retrospectively evaluated the expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD) in 228 and 213 specimens, respectively, from stages I and II breast cancer patients (pts) enrolled in a randomized phase III adjuvant chemotherapy trial comparing epirubicin to CMF, while tamoxifen was given to all postmenopausal pts. The expression of VEGF and MVD was assessed on tissue sections formalin-fixed and paraffin-embedded by immunohistochemical staining using anti-VEGF antibody of human origin and anti-CD34 monoclonal antibody. Univariate and multivariate analysis were performed using chi squared test, log-rank test and Cox's regression model. Sixty four of 228 pts were classified as VEGF positive (28%) with no significant difference in the two treatment arms. In 213 pts evaluated for CD34, 103 pts (48%) were classified as MVD high. No significant association between VEGF and MVD was found, and neither were they correlated with many known prognostic factors such as age, tumor size, nodal status, and histological grade. The only significant correlations observed were between VEGF and estrogen receptor (ER) status (p = 0.013) and between MVD and HER2 overexpression (p = 0.023). At a median follow up of 96 months VEGF and MVD were not correlated with relapse-free survival (RFS) and overall survival (OS) in all pts and in pts assigned to one of the two treatment arms. In conclusion, VEGF and MVD retrospectively evaluated, cannot be considered prognostic factors in node negative (N-) high risk and node positive (N+) breast cancer pts treated with two different regimens of adjuvant chemotherapy.

Quantitative analysis of colorectal tissue microarrays by immunofluorescence and in situ hybridization

The accuracy and reliability of in situ studies may be compromised by qualitative interpretations. Quantitation imposes a greater degree of objectivity, is more reproducible, and facilitates the clarity of definitions. The aim of this study was to validate the utility of laser imaging systems for the in situ quantitative analysis of gene expression in tissue microarrays. Immunofluorescence was employed to quantify the expression of the tumour suppressor p53, a marker of proliferation (Ki67), an endothelial cell marker (CD31), and the mismatch repair proteins human Mut L homologue 1 and human Mut S homologue 2 in an arrayed series of colorectal tissues (n = 110). Quantitative data on this panel of antigens were compared objectively with qualitative scoring of immunohistochemical chromogen deposition. In addition, the expression of vascular endothelial growth factor (VEGF)-A, placental growth factor, hepatocyte growth factor, and c-Met mRNA was quantified by phosphor image analysis of in situ hybridization reactions. The quantified data on p53, Ki67, and CD31 expression were significantly associated with the pathologist's score (p < or = 0.001). While hepatocyte growth factor and placental growth factor were not up-regulated, c-Met expression was increased up to 2.5-fold and the median VEGF-A expression was elevated 4-fold (p = 0.003) in this series of colorectal tumours. Laser imaging systems are therefore feasible for high-throughput, quantitative profiling of tissue microarrays.

Clinical significance of angiogenesis in gastrointestinal cancers: a target for novel prognostic and therapeutic approaches

OBJECTIVE

To review the current data on the prognostic and therapeutic implications of tumor angiogenesis in gastrointestinal cancers.

SUMMARY BACKGROUND DATA

Numerous studies have evaluated the prognostic value of tumor angiogenesis and the potential role of antiangiogenic therapy in various gastrointestinal cancers.

METHODS

A Medline literature search was conducted using "angiogenesis" or the names of various angiogenic factors in combination with the names of gastrointestinal cancers as the key words.

RESULTS

Several studies have demonstrated a significant prognostic impact of tumor microvessel density and tumor expression of angiogenic factors, in particular vascular endothelial growth factor (VEGF), in various gastrointestinal cancers. A few studies have suggested that circulating VEGF might be a useful prognostic marker. However, results were not consistent across all studies and were limited by the retrospective nature of most studies. Antiangiogenic therapy has been shown to be effective against all common gastrointestinal cancers in preclinical studies, but currently there are few clinical data with regard to antiangiogenic therapy in gastrointestinal cancers.

CONCLUSIONS

There is mounting evidence to suggest that assessment of tumor angiogenesis might provide a novel approach of prognostication in patients with gastrointestinal cancers. However, current results from retrospective studies need to be validated by prospective studies. Antiangiogenic therapy is a promising strategy of cancer treatment that might be particularly useful in combination therapy for unresectable cancers or as an adjuvant therapy for resectable tumors.

Predictive markers for colorectal cancer: current status and future prospects

Colorectal cancer (CRC) is the second leading cause of cancer death in the United States. Although there is clear evidence of the benefit of chemotherapy in adjuvant and metastatic settings, its use continues to be suboptimal because of intrinsic or acquired drug resistance. 5-Fluorouracil continues to be the mainstay of CRC therapy, and combinations with newer chemotherapeutic agents such as irinotecan and oxaliplatin have resulted in improved response rates and survival. The role of other agents including cyclooxygenase-2 inhibitors, epidermal growth factor receptor, and farnsyl transferase inhibitors remains to be elucidated. Despite these improvements, many patients undergo chemotherapy without benefit. Increased understanding of the biology of CRC has led to the identification of prognostic markers that may help identify patients who will benefit from chemotherapy. Furthermore, studies have also begun to identify markers that predict whether a tumor will respond to a particular chemotherapy. The ultimate goal of this research is to prospectively identify patients who should receive chemotherapy and, thus, to tailor treatment to the molecular profile of the tumor and patient. Such an approach has the potential to dramatically improve response rates. This review highlights potentially important prognostic and predictive factors in CRC and discusses the potential for their use in the treatment of this disease.

Role of biological markers in the clinical outcome of colon cancer

We investigated a number of biological markers, evaluated under strict intralaboratory quality control conditions, in terms of their role in predicting clinical outcome of patients with colon cancer treated with 5-FU-containing regimens. Colon cancer tissue from 263 patients enrolled onto two randomised clinical trials were studied for their cytofluorimetrically determined DNA content and their immunohistochemically evaluated microvessel density, vascular endothelial growth factor expression, thymidylate synthase expression and tumour lymphocyte infiltration. Disease-free survival and overall survival of patients were analysed as a function of the different variables. At a median follow up of 57 months, age, gender and Dukes' stage showed an impact on disease-free survival, whereas no biological marker emerged as an indicator of better or worse disease-free survival. Only histological grade and Dukes' stage were found to influence overall survival. The different biological variables, studied with particular attention for determination reliability, proved to have no impact on the clinical outcome of patients with colon cancer. Therefore, other markers must be identified to complement clinico-pathological variables in the management of this disease.

The prognostic value of vascular endothelial growth factor in 574 node-negative breast cancer patients who did not receive adjuvant systemic therapy

The growth and metastasising capacity of solid tumours are dependent on angiogenesis. Vascular endothelial growth factor is a mediator of angiogenesis. In this study we investigated whether vascular endothelial growth factor is associated with the natural course of the disease in primary invasive breast cancer. In 574 tumours of patients with node-negative invasive breast cancer the cytosolic levels of vascular endothelial growth factor were measured using a quantitative enzyme-linked immunosorbent assay. These patients did not receive adjuvant systemic therapy and were followed for a median follow-up time of 61 months (range 2-155 months) after the primary diagnosis. Correlations with well-known prognostic factors, and univariate and multivariate survival analyses were performed. Vascular endothelial growth factor level was positively associated with age and tumour size (P=0.042 and P=0.029, respectively). In addition, vascular endothelial growth factor level was inversely, but weakly correlated with progesterone receptor levels (PgR) (r(s)=-0.090, P=0.035). A high vascular endothelial growth factor level (equal or above the median level of 0.53 ng mg(-1) protein) predicted a reduced relapse-free survival and overall survival in the univariate survival rate analysis (for both P=0.005). In the multivariate analysis as well, vascular endothelial growth factor showed to be an independent predictor of poor relapse-free survival and overall survival (P=0.045 and P=0.029, respectively), in addition to age, tumour size and PgR. The results show that cytosolic levels of vascular endothelial growth factor in tumour tissue samples are independently indicative of prognosis for patients with node-negative breast cancer who were not treated with adjuvant systemic therapy. This implies that vascular endothelial growth factor is related with the natural course of breast cancer progression.

Issues and barriers to development of clinically useful tumor markers: a development pathway proposal

There are few tumor markers that are clinically useful in predicting therapeutic responses or patient outcomes despite nearly 20 years of advances in molecular biology. We discuss a variety of issues and barriers that have affected movement of clinical tests from research into clinical practice. Studies of new markers frequently lack clear hypotheses and are generally underpowered to reach statistically valid conclusions. Relevant clinical endpoints may not be possible to evaluate, often leading to suboptimal study designs. Major stumbling blocks exist because studies are rarely comparable. This makes it difficult to determine why results vary from study to study. It also prevents pooling of small datasets for analysis. We propose a tumor marker development pathway that we think will be more efficient and effective. The pathway depends on developing statistically valid study designs, focusing on assay refinement and standardization early in the process, including assay details in publications, and providing data in a format that allows comparison with other studies. The process described should be applicable to development of new technologies that include analysis and interpretation of large, complex datasets. The proposed marker development pathway will require thoughtful refinement and expansion, but it should begin a productive dialog.

An analysis of p53, BAX and vascular endothelial growth factor expression in node-positive rectal cancer. Relationships with tumour recurrence and event-free survival of patients treated with adjuvant chemoradiation

Tumours of patients with node-positive rectal cancer were studied by immunohistochemistry for p53, BAX and vascular endothelial growth factor expressions. Results were correlated to the relapse rate, the pattern of relapse and the event-free survival after radical surgery and adjuvant chemoradiation. After a median follow-up of 60 months, 39 patients remained disease-free and 40 patients relapsed (18 local relapses and 22 distant metastases). The majority of disease-free patients showed p53 negative and vascular endothelial growth factor negative tumours. Local relapses occurred more frequently in patients with p53 overexpressing tumours (P<0.01), while distant metastases were in patients with vascular endothelial growth factor positive tumours (P<0.003). Patients with p53 negative or vascular endothelial growth factor negative tumours showed better event-free survival than patients with p53 positive or vascular endothelial growth factor positive tumours. BAX analysis did not show any association with patients' outcome and it was unrelated to the p53 status. Adjuvant treatment strategies for node-positive rectal cancer may be improved by identifying categories of high-risk patients. In this study, vascular endothelial growth factor and p53 expressions correlated with recurrent disease, pattern of relapse and poor event-free survival.

Differences of vascular endothelial growth factor (VEGF) expression between liver and abdominal metastases from colon cancer. Implications for the treatment with VEGF inhibitors

The vascular endothelial growth factor (VEGF) plays a central role in promoting angiogenesis, and it is the target of innovative anti-cancer therapies. In colorectal carcinomas, differences in the VEGF expression have been found between the primary tumor and its metastases. We postulated that differences in the VEGF expression may also exist between liver and abdominal metastases from colon cancer. Consecutive colon cancer patients with liver or abdominal metastases were considered eligible for the study. Biopsies had to be performed before chemotherapy and the VEGF analysis were conducted through immunohistochemistry. The staining results were correlated to the metastatic pattern. The study population consisted of 41 patients with a metastatic site in the liver in 19 patients and the abdomen in 22 patients. A positive VEGF staining was found in 19 of the 41 metastatic samples (46%). Cases with positive VEGF expression were found more frequently in abdominal (15 out of 22 patients; 68%) than in liver metastases (4 out of 19 patients; 21%). Also, the degree of VEGF immunoreactivity was significantly higher in abdominal than in liver metastases. Evidence is supported that the VEGF expression may be different between colon cancer metastatic sites. The efficacy of anti-VEGF treatments may depend on the VEGF expression status, and this finding deserves further investigation.

Prediction of the response of colorectal cancer to systemic therapy

Adjuvant chemotherapy with fluorouracil and folinic acid improves overall survival for resected carcinoma of the colon of Dukes' stage C by 10-12%. In metastatic disease, response rates with fluorouracil-based regimens are about 25%. Combination with newer agents such as irinotecan and oxaliplatin can improve response rates to more than 50% in selected patients. New treatments with novel molecular targets will soon be entering clinical use. Despite these improvements, many patients undergo chemotherapy for resistant cancer, thus incurring side-effects without benefit. Expression of particular genes can be tested at the protein or RNA level and can be correlated with response or resistance to particular systemic therapies. Thus, predictive-factor testing of tumour biopsy samples may allow us to select chemotherapy or immunotherapy treatments with a high likelihood of benefit for the individual patient.